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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
SCA1 (ATXN1) Repeat Expansion Test
Test Code92903
CPT Codes
81178
Preferred Specimen
8 mL whole blood collected into two EDTA (lavender-top) tubes
Pediatric (0-3 years): 2 mL whole blood
Pediatric (0-3 years): 2 mL whole blood
Minimum Volume
6 mL • Pediatrics: 1 mL
Instructions
Please label each specimen tube with two forms of patient identification. These forms of identification must also appear on the requisition form.
Note: Higher blood volumes ensure adequate DNA quantity, which varies with WBC, specimen condition, and need for confirmatory testing. Patients, 0-3 years have higher WBC, yielding more DNA per mL of blood.
Note: Higher blood volumes ensure adequate DNA quantity, which varies with WBC, specimen condition, and need for confirmatory testing. Patients, 0-3 years have higher WBC, yielding more DNA per mL of blood.
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 10 days
Refrigerated: 10 days
Frozen: Unacceptable
Refrigerated: 10 days
Frozen: Unacceptable
Methodology
Repeat Expansion Detection by Polymerase Chain Reaction
Setup Schedule
Set up: Varies; Report available: 14-21 days
Reference Range
Technical Results:
SfaNI Site Absent-Normal (≤35)
Borderline (36-38)
Positive (≥39)
SfaNI Site Present-Normal (≤44)
Positive (≥45)
SfaNI Site Absent-Normal (≤35)
Borderline (36-38)
Positive (≥39)
SfaNI Site Present-Normal (≤44)
Positive (≥45)
Clinical Significance
Detects CAG triplet repeat expansion in the SCA1 gene. The usual clinical characteristics of the spinocerebellar ataxias are a slowly progressive incoordination of gait that is often associated with poor coordination of hands, speech, and eye movements.
